The car died on me a week ago due to a failed fuel pump. I have since ordered one, and put it in, however, I still can't keep the car running.

It will sometimes start but then die a 1-10 seconds later. I'm sure I am not getting enough fuel pressure.

I just replaced the fuel pump motor, and did not opt for an all new fuel pump assembly.

Is there a trick to putting the pump in the assembly to restore full fuel pressure? I have the bottom pump screen/nipple inserted into the the rubber grommet on the bottom of the assembly housing, and the outlet nipple from the top of the fuel pump motor going into the outlet tube on the top of the assembly. For some reason, I can't get it to push out at a decent enough pressure to run the car appropriately.

 

Fuel lines off the pump probably are OK, most have 2 different sizes, hard to switch them.

There are several threads here and on allpar with similar symptoms, suggest you do a search and read up if you haven't already. Also, are you throwing any codes?

Are you getting any fuel flow at all? If you don't have a way to check the pressure, you can check for flow using the not recommended dirty way and disconnect the line from the pump to the filter at the filter and see if you are getting any flow when you hit the key. The pump will only run for about 2 seconds if the engine doesn't start but I have heard you can use a suitable container to collect it off the line and see what kind of volume you get. Other threads suggest doing it at the throttle body. Either way requires following the depressurization process and great care.

Did you check/change/clean the filter at the pick-up point of the pump before you re-installed? Did you change the external filter?

How much gas is in the tank? You need at least a quarter tank possibly more to have the new pump prime itself.

 

I am not throwing any codes.

I have checked the fuel flow coming out of the fuel filter, and it seems 'ok', but not the best I have seen on other vehicles. I do have fuel at the schrader valve on the fuel rail, but it just kinda dribbles out. I would expect 45 PSI to spray and make the same sound that a tire would.

I installed a new fuel filter when I changed the fuel pump, and the fuel pump motor kit came with a new pickup screen.

The car has a little over a 1/4 tank of gas.

Not having a multimeter handy, I even wired the fuel pump straight to the battery with some wire I had laying around thinking maybe the pump was experiencing some voltage drop, and not allowing it pump at it's full potential, but that was a no go either.

If I block the throttle body intake about 3/4 of the way, and have someone turn the key the car will start and idle fine. I'm assuming this is due to me cutting the amount of air entering the engine to compensate for the lack of fuel, and in turn getting the air/fuel mixture close to what it is suppose to be.

I even took an old fuel pump from a Chevy that I had laying around, wired it up to the battery, ran a fuel line from it to the external fuel filter, and dropped it in a container of gas. The car started up, and ran fine without any issues or prompting from the hand over the intake trick. So I am pretty conclusive it is a fuel pressure issue, but I just bought the fuel pump motor, and here I am.

 

Between the no go with direct wiring and the good running with the external Chevy pump it kinda sounds like you have a bad new pump.

 

How did you diagnose the failed pump in the first place? Is there a chance it was another issue to begin with?

 

Did get it going today long enough for us to take a short test drive, only to get towed back. I think we finally got the fuel pump seated in the properly in the fuel reservoir assembly.

MoparJeff: "Is there a chance it was another issue to begin with"? I'm starting to think that now. Let me explain my diagnoses and the symptoms leading me to believe it was a failing fuel pump.

While driving the car, it would randomly start puttering, jerking, and sometime's give a slight backfire before completely dying within 10-15 seconds of the symptoms. You could count on the car to do this every morning about 10 minutes into your drive. Then it may randomly happen again, or have no problems until the next morning commute.

I used to just start the car right back up, and keep going without too much issue. However, as I let these problems persist, they of course got worse over the coarse of 6 months. The car slowly became increasingly harder to start. Sometimes, I would have to sit on the side of the road for 10-15 minutes, and just let the car sit before it would fire up again, and then other times it would just take a minute or so of me priming the fuel system with the ignition key. That did appear to have some effect on getting the car going again. Learning this, the next time the car acted up I released the fuel pressure out of the fuel rail test port valve, while sitting on the side of the road, to see what kind of pressure would shoot out. Gas did not come spraying out as I would expect at 45 PSI. In fact, I didn't hear a bit of hiss from it, but a little fuel did gurgle out for 1-2 seconds. These symptoms appeared to me as a fuel pump on it's last legs.

Then one morning on the daily commute, the car died, and failed to start again, and was towed at that point.


I don't have access to a fuel pressure gauge, but I do have access to a gauge off a broken compressor. I figured I could just clamp a short piece of rubber fuel tubing onto the gauge. Then remove the stem from the fuel rail Schrader valve using a tire stem remover, and clamp the other end of the rubber tubing over the valve on the fuel rail to see if I am getting 45 PSI. I assume it will be close though, because while out test driving the car this time it ran fine, until the original symptoms appeared again.

The randomness of the symptoms is leading me to believe that this may be an intermittent electrical problem. Especially the way the car just starts to cut in and out before it dies.

Well before I start to worry about that possibility I will get out there tomorrow with my rigged fuel pressure gauge, and verify that the fuel system is operating properly, under starting conditions, and see if the fuel system is really the culprit to the car not wanting to start anymore.

I have already started on the fuel system by replacing the fuel pressure regulator, external fuel filter, and fuel pump so I will test it more accurately with a fuel pressure gauge.

Also, I read about the TSB: 14-01-91
The bulletin details about the SEBC randomly going into an anti-theft mode, involving cars that don't have the factory anti-theft feature, thus, only allowing the car to kick over briefly, and then die. As mine is currently doing at the moment, however, there is times where it will start up and run. Albeit, the distance is short, but shouldn't that rule out this TSB in my case? I did pull the SEBC out today, and took down part number, PN: 4686442. According to the TSB that is the part number that is offered as a revised version to correct this issue.

Am I correct in assuming that my car has the revised SEBC mentioned in the TSB?


Thanks for all the help and input so far.

 

FYI, Autozone has a "Fuel Pump Diagnostic Kit" in their loan-a-tool program, I am sure that others do as well. It has a hefty deposit but you get it back when you return it. Has the correct gauge and fittings to check the pump output accurately. My FSM (for "92 but no doubt similar) has a specific process for running the check.

Based on the prior symptoms, I agree you may be looking at something other than or in addition to the pump. The thing that throws me is that it ran fine with the external pump attached. Browsing through here and allpar seems like there could be a multitude of things, many of which you have addressed. MAP sensors and blocked returned fuel return lines are a couple that seemed to come up frequently. Seems if it was an issue with the throttle body or related inline sensors it would have the same symptoms with the external pump.

If your SEBC has the right P/N then sounds like the TSB was addressed. Doesn't mean it is working correctly now, only that it was serviced at some point.

Another point made in several threads is that on a vehicle of the age ours are a component can have a fail/partial fail without throwing any codes. Or you could have been right from the start and it is the pump and your replacement is bad.

 

I love AutoZone's tool program, unfortunately, I live an hour away from the nearest parts store, which doesn't offer such a service.

Also, I guess I did forget to mention that the MAP sensor was also replaced last week in attempts to resolve this issue.

With the homemade gauge I can perform a Pressure Test at the fuel rail, and if that checks out. I can then perform a Fuel Injector Balance Test to determine if my injectors are at fault in the fuel system.

That should conclude the diagnostics of the fuel system if them two test turn out alright.

If the car is still non-functional at that point, then I'm thinking I should move into testing the ignition system thoroughly. AllData is of no help pertaining to ignition system diagnostic procedures. You wouldn't happen to know the steps necessary to fully diagnose the ignition system or have them handy would you?

Also, is there a way to tell if the SEBC is erroneous without just part swapping a new one in?

 

I don't think your symptoms sound fuel related. I would be looking into sensors and wiring.

 

Ok, so I tested the fuel pressure at the fuel rail. Initially I got 0 PSI after 3 OFF-ON's with the key. I then proceeded to try and start the car. The car turned over for about 15 seconds, and then it started, and the fuel pressure shot up to 80 PSI, but then went down to a little over 45 PSI.

I let the car run for about 5 minutes when it just died again. There was no misfire, stumbling or anything of that nature when it died. It was like a flip of a switch and the engine stopped.

This leads me to believe that it is an electrical or sensor issue.

Where should I start looking first?